From today's environmental perspective, there is an increasing need to develop environmentally friendly industrial practices. Current methods of handling organic waste materials have led to serious pollution problems such as ground water contamination, biological kills, and poor air quality. For example, the common practice of spreading pig and cow manure on fields often gives rise to odor complaints in addition to the resultant loss of intrinsic fertilizer value due to ammonia release.
The present invention relates to the field of composting whereby organic material is decomposed through the action of bacteria. The synthesis of a compost by such methods addresses environmental concerns, especially if the process is carried out under aerobic conditions. Under aerobic control, thermophilic bacteria predominate thus minimizing the production of both noxious and dangerous gases such as hydrogen sulphide and methane often associated with nonaerobic activity. Aerobic conditions are dependent on the efficient passage of an oxygen bearing gas through the organic waste material. Other salient features of aerobic decomposition include the destruction of pathogenic organisms and the retention and fixation of ammonia. For example, temperatures as high as 50-60 degrees Centigrade must be maintained for reasonable periods of time to ensure the complete destruction of illness creating organisms, parasitic eggs, and seeds. Finally, the end product of this compost process has commercial value such as a soil conditioner, and earth improving material, or as a fertilizer.
In summary, the advantages of composting a variety of waste organic material include improved air quality relative to current practice and production of a natural soil conditioner and fertilizer. Also, material is diverted from landfills and waste process streams remain unpolluted. Besides animal manure and sewage sludge, such waste material may include food processing waste, sawmill residue, straw, and other cellulose bearing materials.
The recipe for feed to a compost unit is quite variable and depends on the nature of the main raw material. However, it is clear that the recipe should include both a bulking agent to reduce free moisture and a carbon source to supplement the deficiencies of the basic raw material, thus ensuring proper carbon/nitrogen ratios, sufficient porosity and reasonable NPK values in the final product.
A successful compost apparatus and method is dependent on a balanced recipe suited to the raw feed and local waste materials. Also of critical importance to ensure a homogeneous finely divided product are aerobic thermophilic conditions, proper mixing and agitation.